1. Technical Field
This invention generally relates to computer database systems, and more specifically relates to modification of a saved query based on a change in the meaning of a query value that changes with the passage of time.
2. Background Art
Database systems have been developed that allow a computer to store a large amount of information in a way that allows a user to search for and retrieve specific information in the database. For example, an insurance company may have a database that includes all of its policy holders and their current account information, including payment history, premium amount, policy number, policy type, exclusions to coverage, etc. A database system allows the insurance company to retrieve the account information for a single policy holder among the thousands and perhaps millions of policy holders in its database.
Retrieval of information from a database is typically done using queries. A query usually specifies conditions that apply to one or more columns of the database, and may specify relatively complex logical operations on multiple columns. The database is searched for records that satisfy the query, and those records that satisfy the query are returned as the query result. A problem with using queries to retrieve information from a database is that it typically requires specialized knowledge of a query language, such as Structured Query Language (SQL), as well as detailed knowledge of the database and its relationships. User friendly query interfaces are being developed to provide a graphical query interface that allows a person that does not know SQL to construct queries to a database. For example, IBM Corporation has developed an object oriented framework known as a Data Discovery and Query Builder (DDQB). This framework abstracts out the query layer from the user and lets the user build queries using a graphical interface.
Using a graphical query interface such as the DDQB, a user can construct a query to extract desired information from the database. The graphical query interface allows the user to store the query for later use. However, after the passage of time, some of the values used in the stored query may become outdated. So the same query run in the future may not present the same relative information to the user as was intended when the query was created and saved. Parts of the query that have a time sensitive nature are not taken into consideration for future use of the query.
Without a way to modify the saved query that has time sensitive query values where the meaning of the query values change over time, the computer database industry will continue to suffer from the generation and storing of queries for future use that do not remain useful as the meaning of the values change over time.